By bottom-line answers, I literally mean the answers on the bottom line of a solution.
So if the question requires two pages of math with the final answer that x=5, all I'm interested in is the x=5 part.
In other words, I just want to know whether I've got the correct numerical answer. I'm not asking for a marking rubric or 'model answer', just a verification.
I completely appreciate the arguments against releasing worked solutions. Students can easily be robbed of learning if solutions are readily available to look at. "Oh yeah I'd have done that".
I don't think the arguments about re-using past questions quite apply here - a numerical answer isn't much help and numbers can be changed to screw people who memorise numerical answers.
Are there any other good reasons for not releasing bottom-line answers? It just seems strange to not be able to verify your own work.
EDIT re Dan Romik's comment: My issue here is just one of feedback. If you told me that I'd receive feedback from a lecturer or tutor (or in the real world, client or boss), I'd agree answers are moot. But the reality in university is that a lot of the learning is independent (some lecturers just say "no time" to any request), and answers are a useful feedback mechanism for students to independently spot and diagnose their own flaws.